安徽省扬子鳄饲养种群繁殖力的参数分析及种群增长预测

通过对宣城扬子鳄繁殖研究中心三代繁殖鳄1982—2003年繁殖力有关参数的分析,结果表明近三年来繁殖研究中心扬子鳄产卵量明显减少;亲代受精率为(83.80±2.37)%、孵化率为(89.53±0.86)%;发现F1受精率为(79.38±2.74)%、孵化率为(83.78±1.95)%;F2代个体受精率为(68.7±1.84)%、孵化率为(88.16±1.68)%;通过单因素方差分析F(受精率)=4.33(P<0.05)、F(孵化率)=4.56(P<0.05)差异显著。分析影响扬子鳄繁殖的因素发现:产卵量明显减少可能与亲代鳄逐渐退出繁殖期、F1代鳄整体产卵能力有下降趋势、F2代鳄没有大规模进入繁殖期有关;分析历史资料发现扬子鳄产卵窝数与4月份的温度相关性高(R=0.979,P<0.01);作者认为F1、F2代个体与亲代之间的受精率、孵化率有显著差异,近交衰退、遗传多样性的丧失有密切关系。利用时间序列分析建立理想状态下饲养扬子鳄种群数量估计模型,预测10年内扬子鳄饲养将可能达到19000尾;根据该种群增长模式及种群年龄结构特点,应扩大饲养规模,特别是育成鳄饲养池及幼鳄饲养池的建设。     

盐度对裸项栉鰕虎鱼繁殖和生长的影响

目的探索裸项栉鰕虎鱼繁殖和育苗的适宜盐度。方法比较不同盐度梯度条件下裸项栉鰕虎鱼的产卵率、孵化率和生长存活情况。结果裸项栉鰕虎鱼性腺成熟、产卵和孵化的适宜盐度为10‰-20‰,过低或过高盐度该鱼产卵量少,孵化率极低;适宜的盐度有利于裸项栉鰕虎鱼的生长。结论裸项栉鰕虎鱼适盐范围广,适宜的繁殖、生长盐度较低。     

人工饲料对稀有Ju鲫繁殖影响的研究

静水缸中稀有Ju鲫240天养殖试验显示,A型人工饲料的每对亲鱼产卵次数汉源种群和彭州种群分别为15.25和13.75次,相近于水蚯蚓为饲料的12次和14.5次;A型人工饲料产卵间隔天数分别为15.98天和17.46天,相近于水蚯蚓为饲料的20.86天和16.56天。循环水缸中稀有Ju鲫105天养殖试验显示,A型人工饲料的每对亲鱼产卵次数为12次,低于水蝗蚓为饲料的21.5次;产卵间隔天数为8.75天,长于水蚯蚓为饲料的4.88天。因此,用人工饲料可以实现静水缸和循环水缸中稀有Ju鲫的繁殖。静水缸5种饲料个体每次产卵量有显著差异（P＜0.05）,而鱼卵孵化率没有显著差异（P＞0.05）。A和B型饲料产卵量与水蚯蚓接近。循环水缸4种饲料个体每次卵量和鱼孵化率均有显著差异（P＜0.05）。     

短时高温对金银花贮藏期害虫锯谷盗存活及繁殖的影响

【目的】了解短时高温对金银花Lonicera japonica Thunb.贮藏期害虫锯谷盗Oryzaephilus surinamensis(Linnaeus)存活及繁殖的影响。【方法】在室内测定了锯谷盗成虫经36、39、42、45、48℃高温处1、3、5、7 h后成虫存活率、产卵前期、产卵期、产卵量及F_1代孵化率和羽化率的差异。【结果】短时高温对锯谷盗成虫存活率、产卵前期、产卵期、产卵量及F_1代孵化率和羽化率均有显著影响,在36~48℃范围内,随着温度升高和时间的延长,成虫存活率不断下降、产卵前期不断延长、产卵期不断缩短、产卵量不断下降、F_1代孵化率和羽化率不断下降。经36、39、42、45、48℃高温处理7 h后,成虫存活率分别比对照下降了29.19%、34.47%、39.84%、55.64%和66.68%,产卵前期分别比对照延长了2.06、3.48、4.88、6.51、8.31 d,产卵期分别比对照缩短了4.99、7.89、12.07、16.89、23.14 d,产卵量分别比对照降低了52.26、61.06、70.82、82.87、92.97粒,F_1代孵化率分别比对照下降了21.52%、44.27%、73.44%、97.16%、100%,羽化率分别比对照下降了20.61%、32.85%、57.59%、95.15%、100%。方差分析显示,温度和时间的交互作用对成虫的存活率、F_1代的孵化率和羽化率均有显著影响(P<0.05),而对成虫产卵前期、产卵期和产卵量的影响不显著(P>0.05)。【结论】短时高温对金银花贮藏期害虫锯谷盗存活及繁殖有显著的影响,引起存活率及繁殖力显著下降。     

笼养绿尾虹雉繁殖参数的观察与分析

观察并分析了1993 ～2011年四川蜂桶寨国家级自然保护区笼养绿尾虹雉的产卵数、受精率和产卵持续天数等3个繁殖参数.结果发现,笼养绿尾虹雉的雌鸟平均产卵数为3.62枚(n=19),平均产卵天数为41.63 d(n=19),平均受精率为14.13％ (n=19).与北京笼养种群相关数据比较,其产卵数、产卵持续天数没有显著差异(均P ＞0.05),但受精率远低于北京种群(P＜0.05).     

稀有鮈鲫封闭群Ihb:IHB生长和繁殖性能的监测

目的监测稀有鮈鲫野生型封闭群(Ihb:IHB)建群过程中的生长、繁殖性能,为品种管理和应用提供基础资料。方法对原代(P0)至F4代各50对传代亲鱼的产卵量、产卵间隔、卵膜径、受精率、孵化率进行监测,并对封闭群建群过程中各代(F1~F4)初孵仔鱼全长、7日龄仔鱼全长以及30、60、90日龄时的个体大小进行了监测。结果建群过程中各代间生长呈现一定的差异,F1代初孵仔鱼全长、7日龄全长较F2至F4代大,但30日龄后F2至F4代的生长指标高于F1代。培育封闭群过程中各代的受精率、孵化率有一定波动,但均维持在较高水平;各代间的产卵间隔差异并无显著性,P0代的产卵量和卵膜径大于F1至F4代。结论各代的生长差异可能与饲养条件有关,原代产卵量较大与其亲本个体较大有关;世代更替过程中封闭群保持了较高的生长和繁殖性能,未发现随世代更替而出现逐渐增大或者减小的现象,符合实验动物封闭群的要求。     

稀有鮈鲫封闭群 Ihb: IHB 生长和繁殖性能的监测简

目的 监测稀有鮈鲫野生型封闭群（Ihb：IHB）建群过程中的生长、繁殖性能,为品种管理和应用提供基础资料.方法 对原代（P0）至F4代各50对传代亲鱼的产卵量、产卵间隔、卵膜径、受精率、孵化率进行监测,并对封闭群建群过程中各代（F1~F4）初孵仔鱼全长、7日龄仔鱼全长以及30、60、90日龄时的个体大小进行了监测.结果 建群过程中各代间生长呈现一定的差异,F1代初孵仔鱼全长、7日龄全长较F2至F4代大,但30日龄后F2至F4代的生长指标高于F1代.培育封闭群过程中各代的受精率、孵化率有一定波动,但均维持在较高水平;各代间的产卵间隔差异并无显著性,P0代的产卵量和卵膜径大于F1至F4代.结论 各代的生长差异可能与饲养条件有关,原代产卵量较大与其亲本个体较大有关;世代更替过程中封闭群保持了较高的生长和繁殖性能,未发现随世代更替而出现逐渐增大或者减小的现象,符合实验动物封闭群的要求.     

年龄对朱鹮繁殖成功率的影响

本文对陕西洋县16年间朱鹮(Nipponia nippon)年龄对繁殖成功率的影响进行了研究,结果表明:朱鹮首次参加繁殖的平均年龄为3.89±1.40年(n=73),雌雄分别为3.64±1.36年(n=37)和4.17±1.47年(n=36),差异不显著。2-3龄亲鸟的平均窝卵数、孵化率和出飞率显著低于4-10龄的繁殖个体;>10龄繁殖个体的产卵数和卵的受精率显著降低,但雏鸟成活率较高。三个年龄组之间的繁殖成功率无显著差异(F2,146=1.963,P=0.144)。随着雌雄亲鸟年龄的增长,幼鸟的出飞率显著增加。刚参加繁殖的2龄雌性产卵数很低(2.63±0.74,n=8),至5龄时达到最大值(3.2±0.92,n=10)。6-9龄的雌雄个体产卵数量处于相对的低峰,10龄左右有所恢复(3.0±0,n=3),此后维持一个相对较低的水平(2.55±0.99,n=20)。刚参加繁殖的雄性朱鹮(2年)形成的配对卵的孵化率较低(0.67±0.29,n=3),但在第二年迅速达到高峰,而且能维持5-6年的时间。9-10年时略有下降(0.88±0.18,n=2;0.93±0.17,n=3),10年以后维持在一个较低的水平上(0.56±0.51,n=19)。     

三线闭壳龟繁殖生态的研究

在暨南大学爬行动物养殖场对三线闭壳龟的繁殖生态进行了研究。结果显示:三线闭壳龟每年产卵1次,每次产卵平均3.6枚。受精卵长径为48.00±2.63mm,短径为26.42±1.66mm,卵重为23.89±3.34g。未受精卵长径为44.35±4.36mm,短径为25.39±2.71mm,卵重为20.39±4.96g。卵的受精率为50.9%,孵化率为83.3%,孵化期平均88d,估计积温为59.581℃·h。稚龟的背甲长为44.83±2.41mm,背甲宽为36.90±1.86mm,体重为15.85±2.07g。     

高温条件下茶尺蠖核型多角体病毒对茶尺蠖繁殖的影响

本文报告了高温季节茶尺蠖核型多角体病毒对其宿主繁殖的影响。结果表明,免于病死的雌性蛹、成虫的卵巢发育进度与对照相比,无显著性差异;3龄末和4、5龄初饲毒后,化蛹率与羽化率极显著下降,交配率一股明显下降,而羽化成虫的产卵前期、寿命、产卵量、总怀卵量及卵孵化率与对照相比并无显著差异。成虫饲毒后,繁殖力不受影响。     

The effect of alternative mating tactics on the fertilization success of a hermaphroditic seabass

In the simultaneously hermaphroditic marine fish, Serranus subligarius, male role individuals are known to pair spawn, group spawn and streak spawn. While the effects of these common mating tactics on mating success in the male role have been well studied, their consequences for the reproductive success of the individuals taking the female role have received little attention. To investigate those consequences, I observed mating behaviors and quantified fertilization success in natural and experimental settings during the summers of 2005-2008 at three sites with different local population densities. I observed focal individuals in 15-min increments and recorded the total number of spawns, number of streak spawns, size of participating spawners, and fertilization rate. The occurrence of small-sized individuals in the local population is associated with higher frequencies of streaking behavior; these small fish are most often first-year individuals reaching sexual maturity late in the spawning season (August/September). Spawns that included one or more streak spawners had a significantly lower average fertilization rate (89?%) than pair spawns without a streak spawner (97?%). This pattern was confirmed with a field manipulation experiment in which spawning events that included streakers again showed lower fertilization rates (93?%) than spawning events that did not include streakers (98?%). These lower fertilization rates occurred despite the fact that spawns that included multiple males produced, on average, 20?% more sperm than produced in spawns with only a single male. These results indicate that females incur a significant fitness cost when streakers invade a spawning event, a cost not attributable to sperm limitation or any direct effects on the female.     

Divergence in reproductive ecology of the three-spined stickleback,Gasterosteus aculeatus

An anadromous population (trachurus form) and three freshwater populations (leiurus form) of the three-spined stickleback,Gasterosteus aculeatus, in central Japan were compared with one another in the reproductive traits: body length at maturity, egg size, clutch size, the swell of abdomen and the number of eggs per nest. The anadromous fish which become larger in body size at maturity spawn eggs smaller in size and greater in number than the freshwater fish. The abdomen swell of gravid females expressed by the proportion of abdomen width to body length was greater in the freshwater fish. The anadromous male fish collected a mean of 2,638 eggs with a range of 1,119 to 4,052 eggs from about 6–7 females. In the three freshwater (the Yamayoke, the Tsuya and the Jizo) populations, males must have mated with about 9–22, 7–18 and 4–7 females respectively. It seems that theleiurus form increases its reproductive success by its much more mating opportunities and the parental efforts of nesting males as well as by spawning large eggs. Furthermore, among the freshwater populations, the Jizo one inhabiting the upper stream was clearly larger in body size, in egg size and in clutch size than the Yamayoke and the Tsuya ones which inhabit stable waterbodies with springs. It is possible that the Jizo population adopted the strategy of spawning a few large eggs as an adaptation to its habitat. The causal and functional explanations in reproductive characteristics among the four populations are discussed in regard to differences in the environmental conditions.     

Spawning related movement of shovelnose sturgeon in the Missouri River above Fort Peck Reservoir,Montana

The hypotheses of this study were (i) that shovelnose sturgeon would make upstream movements to spawn, (ii) movement of spawning fish would be greater in a year with higher discharge, and (iii) that spawning fish would have greater movements than reproductively inactive fish. Shovelnose sturgeon Scaphirhynchus platorynchus (Rafinesque, 1820) in five reproductive categories (e.g. males, confirmed spawning females, potentially spawning females, atretic females, and reproductively inactive females) were tracked in 2008 and 2009. All reproductive categories, except reproductively inactive females, exhibited large‐scale movements and had omnidirectional movements. No differences in movement rates were observed in confirmed spawning females between years despite a 45% higher peak discharge in 2008 (839 m³ s^?1) than in 2009 (578 m³ s^?1). A peak discharge was obtained at a faster rate in 2008 (165 m³ s^?1 day^?1) than in 2009 (39 m³ s^?1 day^?1), and high discharge was of greater duration in 2008. Reproductively inactive females did not exhibit large‐scale movements and their movement rate differed from other reproductive categories. Shovelnose sturgeon spawned in both years, despite highly varying hydrographs between years.     

Thermal heterogeneity,migration, and consequences for spawning potential of female bull trout in a river–reservoir system

The likelihood that fish will initiate spawning, spawn successfully, or skip spawning in a given year is conditioned in part on availability of energy reserves. We evaluated the consequences of spatial heterogeneity in thermal conditions on the energy accumulation and spawning potential of migratory bull trout (Salvelinus confluentus) in a regulated river–reservoir system. Based on existing data, we identified a portfolio of thermal exposures and migratory patterns and then estimated their influence on energy reserves of female bull trout with a bioenergetics model. Spawning by females was assumed to be possible if postspawning energy reserves equaled or exceeded 4 kJ/g. Given this assumption, results suggested up to 70% of the simulated fish could spawn each year. Fish that moved seasonally between a cold river segment and a warmer reservoir downstream had a greater growth rate and higher propensity to spawn in a given year (range: 40%–70%) compared with fish that resided solely in the cold river segment (25%–40%). On average, fish that spawned lost 30% of their energy content relative to their prespawn energy. In contrast, fish that skipped spawning accumulated, on average, 16% energy gains that could be used toward future gamete production. Skipped spawning occurred when water temperatures were relatively low or high, and if upstream migration occurred relatively late (mid‐July or later) or early (early‐May or earlier). Overall, our modeling effort suggests the configuration of thermal exposures, and the ability of bull trout to exploit this spatially and temporally variable thermal conditions can strongly influence energy reserves and likelihood of successful spawning.     

Reproductive regulation in the female Japanese minnow, Pseudorasbora parva (Cyprinidae)

The Japanese minnow, Pseudorasbora parva, is a multiple spawner that lays eggs repeatedly during the spawning season. In laboratory aquaria, 19 of 63 females did not spawn, whereas 44 other females laid 167 to 6285 eggs in 1 to 14 mating sequences. Neither fish density nor sex ratio (number of males per female) affected fecundity, but the increase in fish density significantly decreased the growth rate of females. The increase in male length significantly increased fecundity in aquaria which contained only a single male, whereas it decreased female growth rate. These relationships were not evident in aquaria housing three or ten males. Since larger males were more dominant and had larger testes than smaller males, the correlation between fecundity and male size strongly suggests that individual females regulated fecundity to increase their reproductive success.     

Spawning behavior ofChaetodon multicinctus (Chaetodontidae); pairs and intruders

Synopsis Spawning by the banded butterflyfish,Chaetodon multicinctus (Chaetodontidae) was observed on coral reefs off Kona, Hawaii. These fish occurred in male-female pairs during normal daytime activities, a behavior which is typical for the family. Courtship is also a paired male-female activity. During spawning, however, other individuals (males?) may intrude on the spawning pair. Spawning typically takes place at least a meter or two above the bottom. The spawning position consists of the male below and behind the female with his snout against the female's ventral flank or anal fin area. Intruding individuals may join in when the pair is in position and about to spawn. Intruders line-up against the male in the same position as he is against his female. Underwater photographs are included to illustrate these behaviors.     

The effect of stress on reproduction in Atlantic cod

This study imposed stress upon spawning cod Gadus morhua in the laboratory to evaluate the potential effects of trawl avoidance on their reproductive physiology and spawning behaviour. Plasma cortisol levels of stressed fish were significantly higher than controls. Stressed cod initiated fewer courtships and often performed an altered courtship sequence. Both control and stressed fish spawned and there was little difference in the production of eggs, fertilization rate, hatching success or time to starvation of larvae. However, stressed fish produced abnormal larvae more frequently. Cod exposed to a chronic stressor are able to spawn successfully, but there appears to be a negative impact of this stress on their reproductive output, particularly through the production of abnormal larvae.     

Females solicit sneakers to improve fertilization success in the bitterling fish (Rhodeus sericeus)

In most species there is greater variance in reproductive fitness among males than females. A consequence is the evolution of alternative male mating tactics, including sneaking behaviour whereby males attempt to mate with females courted by other males, which could undermine female choice. In bitterling (Rhodeus sericeus), fish that lay their eggs on the gills of living freshwater mussels, sneaking is common and successful. Here we show that female bitterling can significantly improve their fertility with an increase in the number of spawning partners. Females perform conspicuous behaviours associated with spawning more frequently close to sneakers, and spawn more eggs close to high-quality sneakers. This is the first time that females have been shown to engage in behaviour that increases the probability of sneaking, and raises the possibility of a sexual conflict over the number and source of ejaculates during spawning in this species.     

Allis shad adopts an efficient spawning tactic to optimise offspring survival

The potential effects of global warming on the allis shad population were tested by combining a time series of spawning acts with expected thermal survival rates for embryos and larvae until 14 days post hatching. The yearly mean survival of spawn for each reproductive season was calculated and an index of reproductive efficiency based on this survival rate was proposed. The randomness of the spawning tactics was evaluated by shuffling the spawn acts time series. This approach was applied to the Gironde-Garonne-Dordogne (south-west France) population, which recently collapsed. The yearly mean thermal survival of spawn is slightly variable at approximately 55% over 2003–2012 despite fluctuating temperatures. An especially low survival (35%) was recorded for the last season (2013). For eight of the 11 reproductive seasons, the index of reproductive efficiency was high (> 80%) and largely above indices obtained by a random spawning tactic. Therefore shad are able to adopt an efficient spawning tactic to anticipate favourable thermal conditions for survival of their offspring. However, thermal behavioural rules still need to be expanded to understand the failures in their reproduction efficiency.     

Spawning frequency of brood dams and sires in a marine fish stock‐enhancement hatchery

Parentage analysis, employing five hypervariable microsatellite markers, was used to follow spawning patterns of red drum Sciaenops ocellatus broodfish in two spawning tanks through most of a calendar year in a marine fish hatchery dedicated to stock enhancement. Five of six dams and all four sires spawned at least once during the year. Variation in dam and sire spawning incidence and in number of progeny produced per dam and per sire translated into reduced genetic effective size (N_e) per spawn by 40·6% in one tank and 50·8% in the other.